Polymorphisms influencing prostate-specific antigen concentration may bias genome-wide association studies on prostate cancer

Interleukins-6 -174G/C (rs1800795) and -572C/G (rs1800796) polymorphisms and prostate cancer risk

Prostate cancer (PCa) is an aggressive cancer influenced by a complex interplay of genetic and environmental factors. Amongst these risk factors, the impact of Interleukin6 (IL6) gene polymorphisms in PCa risk has received a lot of attention. IL-6 is a cytokine that has been implicated in the pathogenesis of several malignancies, including PCa. Two IL-6 gene polymorphisms, - 174 G/C (rs1800795) and - 572 C/G (rs1800796), have received intellectual attention due to their potential role as modulators of prostate cancer risk. The main objective of this research was to comprehensively explore the potential associations between IL-6 rs1800795 and rs1800796 polymorphisms, and their impact on the occurrence of PCa. A case-control study was carried out with a well-defined cohort comprising 110 PCa cases and 110 controls (total n = 220). The genotyping of rs1800795 and rs1800796 was carefully performed using the highly sensitive and accurate Polymerase Chain Reaction-High Resolution Melting Curve (PCR-HRM) technique. The assessment of genetic associations was evaluated using various R packages, such as Haplo-Stats, SNP stat, pheatmap, and LD heatmap. The present study applied odds ratio (OR) analysis to reveal significant evidence of strong associations between the genotypes of rs1800795 and rs1800796 and the susceptibility to PCa. The findings of this study underscore the noteworthy impact of genetic variations in the IL-6 gene on the development of prostate cancer. Specifically, the C/G and G/G genotypes of rs1800795 demonstrated increased PCa risk, with odds ratios (OR) of 1.650 (95% CI = 1.068-2.549, p = 0.032) and 2.475 (95% CI = 1.215-5.043, p < 0.001), respectively. Similarly, the G/C genotype of rs1800796 exhibited an OR of 2.374 (95% CI = 1.363-4.130, p = 0.012) for elevated prostate cancer risk, while the C/C genotype had an OR of 1.81 (95% CI = 1.02-3.22, p = 0.7). Furthermore, our haplotype analysis have revealed an association between haplotype 4 (C-G) and increased risk of PCa (OR = 1.69, 95% CI = 1.05-2.73, p = 0.032). In conclusion, this case-control analysis presents compelling evidence for a significant association between IL-6 variants (rs1800795 and rs1800796) and increased susceptibility to prostate cancer.

Genome-wide association study of prostate-specific antigen levels identifies novel loci independent of prostate cancer

Prostate-specific antigen (PSA) levels have been used for detection and surveillance of prostate cancer (PCa). However, factors other than PCa—such as genetics—can impact PSA. Here we present findings from a genome-wide association study (GWAS) of PSA in 28,503 Kaiser Permanente whites and 17,428 men from replication cohorts. We detect 40 genome-wide significant (P<5 × 10⁻⁸) single-nucleotide polymorphisms (SNPs): 19 novel, 15 previously identified for PSA (14 of which were also PCa-associated), and 6 previously identified for PCa only. Further analysis incorporating PCa cases suggests that at least half of the 40 SNPs are PSA-associated independent of PCa. The 40 SNPs explain 9.5% of PSA variation in non-Hispanic whites, and the remaining GWAS SNPs explain an additional 31.7%; this percentage is higher in younger men, supporting the genetic basis of PSA levels. These findings provide important information about genetic markers for PSA that may improve PCa screening, thereby reducing over-diagnosis and over-treatment.

Prostate-specific antigen is used as a biomarker of prostate cancer, but levels can be affected by other factors not related to cancer. Here, the authors find genes associated with prostate specific antigen levels in healthy men, which could be used to reduce over-diagnosis and over-treatment.

Variation in genes involved in the immune response and prostate cancer risk in the placebo arm of the Prostate Cancer Prevention Trial

BACKGROUND

We previously found that inflammation in benign prostate tissue is associated with an increased odds of prostate cancer, especially higher-grade disease. Since part of this link may be due to genetics, we evaluated the association between single nucleotide polymorphisms (SNPs) in immune response genes and prostate cancer in the placebo arm of the Prostate Cancer Prevention Trial.

METHODS

We genotyped 16 candidate SNPs in IL1β, IL2, IL4, IL6, IL8, IL10, IL12(p40), IFNG, MSR1, RNASEL, TLR4, and TNFA and seven tagSNPs in IL10 in 881 prostate cancer cases and 848 controls negative for cancer on an end-of-study biopsy. Cases and controls were non-Hispanic white and frequency matched on age and family history. We classified cases as lower (Gleason sum <7; N = 674) and higher (7-10; N = 172) grade, and used logistic regression to estimate odds ratios (OR) and 95% confidence intervals (CI) adjusting for age and family history.

RESULTS

The minor allele (C) of rs3212227 in IL12(p40) was associated with an increased risk of total (log additive: OR = 1.30, 95%CI 1.10-1.53; P-trend = 0.0017) and lower-grade (OR = 1.36, 95%CI 1.15-1.62; P-trend = 0.0004) prostate cancer. The minor allele (A) of rs4073 in IL8 was possibly associated with a decreased risk of higher-grade (OR = 0.81, 95%CI 0.64-1.02; P-trend = 0.07), but not total disease. None of the other candidates was associated with risk. The minor alleles of IL10 tagSNPs rs1800890 (A; OR = 0.87, 95%CI: 0.75-0.99; P-trend = 0.04) and rs3021094 (C; OR = 1.31, 95%CI 1.03-1.66, P-trend = 0.03) were associated with risk; the latter also with lower- (P-trend = 0.04) and possibly higher- (P-trend = 0.06) grade disease. These patterns were similar among men with PSA <2 ng/ml at biopsy.

CONCLUSION

Variation in some immune response genes may be associated with prostate cancer risk. These associations were not fully explained by PSA-associated detection bias. Our findings generally support the role of inflammation in the etiology of prostate cancer.

A study of molecular signals deregulating mismatch repair genes in prostate cancer compared to benign prostatic hyperplasia

Prostate cancer is one of the leading causes of mortality among aging males. There is an unmet requirement of clinically useful biomarkers for early detection of prostate cancer to reduce the liabilities of overtreatment and accompanying morbidity. The present population-based study investigates the factors disrupting expression of multiple functionally related genes of DNA mismatch repair pathway in prostate cancer patients to identify molecular attributes distinguishing adenocarcinoma from benign hyperplasia of prostate. Gene expression was compared between tissue samples from prostate cancer and benign prostatic hyperplasia using real-time-PCR, western blot and immunohistochemistry. Assessment of genotypes of seven single-nucleotide-polymorphisms of three MMR genes was conducted using PCR-coupled RFLP and sequencing. Promoter methylation was interrogated by methylation-specific-PCR and bisulfite-sequencing. Interaction between microRNAs and MMR genes was verified by 3'UTR-based dual luciferase assays. Concurrent reduction of three MMR genes namely hMLH1, hMSH6 and hMSH2 (34-85%, P<0.05) was observed in prostate cancer tissues. hMSH6 polymorphism rs1800932(Pro92Pro) conferred a borderline protection in cancer patients (OR = 0.33, 95% CI = 0.15-0.75). Relative transcript level of hMLH1 was inversely related (r = -0.59, P<0.05) with methylation quotient of its promoter which showed a significantly higher methylation density (P = 0.008, Z = -2.649) in cancer patients. hsa-miR-155, hsa-miR-141 and hsa-miR-21 gene expressions were significantly elevated (66-85%, P<0.05) in tumor specimens and negatively correlated (r = -0.602 to -0.527, P<0.05) with that of MMR genes. hsa-miR-155 & hsa-miR-141 and hsa-miR-155 & hsa-miR-21 were demonstrated to bind to their putative seed sequences in hMLH1 and hMSH6 3'UTRs respectively. Relatively higher expression of DNA methyl-transferases (DNMT1 and DNMT3b) and HIF-1α genes (34-50%, P<0.05) were also detected in tumor tissues. This study provides statistical evidence that MMR deficiency is correlated with hypermethylation of hMLH1 promoter and upregulation of hsa-miR-155, hsa-miR-141 and hsa-miR-21 in prostate cancer. This comparative study reflects that microRNA expression level, particularly hsa-miR-155, exhibits predictive signature of prostate adenocarcinoma.